The topic of fire risk on battery electric vehicles (EVs) is one that fans of battery EVs find very offensive. They believe that news reports of EVs catching fire is part of a wider anti-EV conspiracy, propagated by legacy car makers like Toyota, exaggerated by the media who conveniently ignore the many more cases of internal combustion engine (ICE) cars catching fire.
Yes, it is true that EVs don’t catch fire any more than regular combustion engine cars. The problem is that when an EV catches fire, it burns so spectacularly that no fire-fighting equipment can contain it, and it will keep reigniting over and over again, for days – a situation known as thermal runaway.
The only sure way of permanently putting out a burning EV is to lift the car by crane and dunk it into a pool of water – this may not be possible if the car is stuck in a difficult position (on a slope, like Hammond’s incident in the Grand Tour), or in an underground car park.
The only sure way to put an EV fire is to use an immersion tank, as demonstrated by the German fire department using a PHEV BMW i8
Conversely, a burning combustion engine car will put itself out when there is nothing left to burn, and regular fire extinguishers are effective enough against it. Often, by the time firefighters arrive, the fire would’ve already died down and only a smouldering mess remain.
Earlier this month in Busan, Korea, two people died after their slammed into a toll booth barrier. The car ignited within 3 seconds and firefighters couldn’t stop the fire.
News reports show firefighters with breathing apparatus (burning batteries release acrid, very toxic gases) had to keep dousing the car with water even after the fire had been put out, because thermal runaway in the battery will cause it to reignite once more.
Even though the fire has been put out (for now), firefighters had to keep dousing the battery section with water to stop it from reigniting
The car just kept burning over and over again, and the fire department had to bring in a special tool to build a makeshift pool around the car, flooding the lower part of the car to keep the floor-mounted battery cool.
Without a crane and a full size immersion tank, Korean firefighters built this makeshift pool to flood the Ioniq 5's battery
Preliminary investigations show the occupants didn’t die from the fire (soot was not found in the deceased’s respiratory tracts), but from the collision itself, which was estimated to be 80 to 90 km/h. No brakes were applied prior to the collision. The occupants also weren’t wearing their seatbelts, and investigation show that dummy seat belt clips were used to defeat the seat belt warning chime.
The widely publicised incident quickly became a trending topic on Korean social media space, leading to posts of even more fire incidents involving the Ioniq 5, including the one shown below.
The incident gained greater attention than it normally would in another country because in Korea, EVs have been associated with fire risk, following many high profile fires involving the . The model has since been discontinued in Korea, though an improved version of the car is still available in other countries including Malaysia and Indonesia.
Earlier this year in January, a in Korea that had already underwent a battery replacement recall, caught fire while it was being driven. The driver escaped unharmed.
“I am not trying to criticize EVs because I myself own an EV. But rather, I am asking the automakers to improve battery-related safety. I know it must be difficult to find the cause of the battery catching fire, but I am sure they have an idea of what went wrong,” a 31-year-old Ioniq 5 owner told The Korea Herald.
Statistics from the National Fire Research Institute of Korea show that in 2020, EVs were responsible for only 0.52 percent of recorded cases of burning cars, while combustion engine cars were responsible for 1.88 percent of fires.
But that's also because EVs now constitute only a very small percentage of cars on the road. As battery EVs become more common, the Korean fire department is evaluating several options in battling EV fires, including use of fire suppresent blankets and special tools to quickly build a cooling pool around the car, as demonstrated below:
This mobile water pool is among methods evaluated by the Korean fire department, but lifting the car to put water leak resistant layer under the car is difficult, especially when EVs weigh over 2 tonnes
The Korea Battery Industry Association say one solution to reduce risk of thermal runaways is to use solid-state batteries.
“There are no statistics showing that fire risks are higher for EVs than combustion engine cars. The industry is doing its best to enhance battery safety and one solution is to successfully develop an all-solid-state battery,” said a spokesperson for the battery manufacturer association.
After the burning EV is dunk into a pool, it needs to be towed to an open field because it could still could catch fire again
As its name implies, solid-state batteries are solid and don’t need electrolyte liquids inside – which degrade with every charge-discharge cycle – to facilitate the movement of ions.
Toyota LQ prototype is a road legal EV (with license plates) running on solid-state batteries. To ensure safety and Corolla-level reliability, Toyota developed a world's first method of studying EV batteries on a particle level, using Japan's SPring-8 synchrotron radiation facility
Toyota will be putting solid-state batteries into production cars by 2025, but it will be rolled out first in hybrids rather than battery EVs, for the simple reason that hybrids use smaller, cheaper batteries, and the cost of solid-state batteries are still too high for EVs.
Several Chinese manufacturers have also demonstrated working prototypes with solid state batteries, but none is ready for commercial sales yet.
Keyword: Firefighters struggle to put out a burning Hyundai Ioniq 5, triggers EV scare in Korea but what does data on EV fires say?